Growing in our prayer life can be a challenging but rewarding experience. The best way to learn to pray is to simply tell God “where you are and what is on your mind.” (Paul Miller)  However, I have found that reading from authors with a passion for prayer, grows my desire to pray. I recommend the following books on prayer.   
1)  A Praying Life: Connecting with God in a Distracting World by Paul Miller.  Readable, practical and insightful. 
2) Prayer: Experiencing Awe and Intimacy with God by Tim Keller. 
Whatever Tim Keller writes, I make every effort to read. His book on prayer is worth reading multiple times. 
3) The Complete Book of Prayer by E.M. Bounds. 
Simply a classic on the topic.
Pastor Dusty